Although there is general agreement that doctoral students and their experiences are diverse, in what respect this is true is in question. Most institutional practices in the collection of data in this regard have been established to satisfy government reporting requirements and concerns, such as funding, participation and equity, and efficiency. Missing is more detailed and nuanced quantitative data and analysis, complementary to those of qualitative studies, to illuminate the nature and extent of doctoral student diversity and the effects on the quality of their candidacy. Drawing on select data and findings from a national survey of Australian doctoral candidates conducted in 2005, the article questions the utility of commonly used categories for quantitative data collection and analysis, and their use as the basis of (sub)groupings to represent doctoral diversity. In so doing, it presents a more complex picture of doctoral candidature that depicts the idiosyncrasy of the individual experience, as well as generic characteristics. Central to the argument is that doctoral candidates are diversely different, bringing varying goals, expectations, career histories and family and community responsibilities beyond the academy, that shape their engagement with their candidacy. (Contains 6 tables.)